Grating couplers, which have large alignment tolerance and are capable of accommodating large bandwidth, are useful for interconnecting single mode fibers. However, due to the usage of conventional fiber block for the packaging of a device, grating couplers do not free the top surface of a device for electrical and thermal connections and active device integrations. As a result, in order to free up top surfaces for electrical and thermal connectivity, edge coupling has been proposed.
Accordingly, there is a need for a grating coupler which can be used in an edge coupling configuration and free up top surfaces of devices for integration.